It is well known in the art that ferromagnetic chromium dioxide possesses many desirable characteristics which make it useful for certain applications in the manufacture of magnetic recording tapes, magnetic memory recorders, computers and other applications. The preparation of ferromagnetic chromium dioxide is described in U.S. Pat. Nos. 2,956,955; 3,117,093; and 3,278,263 (Cox), among others.
The Cox patent discloses a batch process for the manufacture of ferromagnetic chromium dioxide through thermal decomposition of a chromium (III) compound combined with oxygen, or a hydrated form thereof; with modifying agents including antimony compounds and iron compounds. The process is carried out in an oxidizing environment using a paste with a water content of from 5 to 30%, pressures of 50 to 3000 atmospheres and temperature of 250.degree. to 500.degree. C. One disadvantage of this process is that the synthesis is a lengthy batch process, in which the ferromagnetic chromium oxide product forms as a solid block which is fused to the interior of the reaction vessel. This block must be mechanically drilled out in order to recover the product. There is need for a continuous process of synthesizing ferromagnetic chromium oxide, in place of the batch process and its attendant problems.